| Copyright © 1997, 1998 ARM Limited. All rights reserved. | ARM DUI 0040D |
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Regular expressions are the means by which you specify and match strings. A regular expression is either:
a single extended ASCII character (other than the special characters described below)
a regular expression modified by one of the special characters.
You can include low level symbols or high level symbols in a regular expression (see High level and low level symbols for more information.)
Pattern matching is done following the UNIX regexp(5) format,
but without the special symbols, ^ and $.
The following special characters modify the meaning of the previous regular expression, and work only if such regular expression is given:
*Zero or more of the preceding regular expressions.
For example, A*B would match B, AB,
and AAB.
?Zero
or one of the preceding regular expression. For example, AC?B matches AB and ACB but
not ACCB.
+One
or more of the preceding regular expression. For example, AC+B matches ACB and ACCB,
but not AB.
The following special characters are regular expressions in themselves:
\Precedes any special character that you want to
include literally in an expression to form a single regular expression.
For example, \* matches a single asterisk (*)
and \\ matches a single backslash (\).
The regular expression \x is equivalent to \x as
the character x is not a special character.
()Allows
grouping of characters. For example, (202)* matches 202202202 (as
well as nothing at all), and (AC?B)+ looks for
sequences of AB or ACB, such
as ABACBAB.
.Exactly
one character. This is different from ? in that
the period (.) is a regular expression in itself,
so .* matches all, while ?* is
invalid. Note that . does not match
the end-of-line character.
[ ]A
set of characters, any one of which can appear in the search match.
For example, the expression r[23] would match
strings r2 and r3. The expression [a-z] would
match all characters between a and z.
| Copyright © 1997, 1998 ARM Limited. All rights reserved. | ARM DUI 0040D |
| PDF version | |
| Home > ARM Debuggers for Windows and UNIX > Debugger further details > Using regular expressions |